Bugfix [#29064] armature with curve contraint - crash

Spline IK and Auto-IK working together on the same bone chain could
crash due to the somewhat hacky way that they were sharing the same
list for the "iktree" forest. Resolved by doing what I should have
done from the beginning, and made Spline-IK save its ik chains off
into a separate list.

While this fixes the crash, it might be worth investigating outright
disabling this from working in this case, since it can be a bit
confusing to have it appear to not work.

4 files changed, 24 insertions, 22 deletions

diff --git a/source/blender/blenkernel/intern/armature.c b/source/blender/blenkernel/intern/armature.c
index 50f305e4400..a9c29728650 100644
--- a/source/blender/blenkernel/intern/armature.c
+++ b/source/blender/blenkernel/intern/armature.c
@@ -1818,7 +1818,7 @@ static void splineik_init_tree_from_pchan(Scene *scene, Object *UNUSED(ob), bPos
 		tree->ikData= ikData;
 		
 		/* AND! link the tree to the root */
-		BLI_addtail(&pchanRoot->iktree, tree);
+		BLI_addtail(&pchanRoot->siktree, tree);
 	}
 	
 	/* mark root channel having an IK tree */
@@ -2045,27 +2045,24 @@ static void splineik_execute_tree(Scene *scene, Object *ob, bPoseChannel *pchan_
 	tSplineIK_Tree *tree;
 	
 	/* for each pose-tree, execute it if it is spline, otherwise just free it */
-	for (tree= pchan_root->iktree.first; tree; tree= pchan_root->iktree.first) {
-		/* only evaluate if tagged for Spline IK */
-		if (tree->type == CONSTRAINT_TYPE_SPLINEIK) {
-			int i;
-			
-			/* walk over each bone in the chain, calculating the effects of spline IK
-			 * 	- the chain is traversed in the opposite order to storage order (i.e. parent to children)
-			 *	  so that dependencies are correct
-			 */
-			for (i= tree->chainlen-1; i >= 0; i--) {
-				bPoseChannel *pchan= tree->chain[i];
-				splineik_evaluate_bone(tree, scene, ob, pchan, i, ctime);
-			}
-			
-			/* free the tree info specific to SplineIK trees now */
-			if (tree->chain) MEM_freeN(tree->chain);
-			if (tree->free_points) MEM_freeN(tree->points);
+	while ((tree = pchan_root->siktree.first) != NULL) {
+		int i;
+		
+		/* walk over each bone in the chain, calculating the effects of spline IK
+		 * 	- the chain is traversed in the opposite order to storage order (i.e. parent to children)
+		 *	  so that dependencies are correct
+		 */
+		for (i= tree->chainlen-1; i >= 0; i--) {
+			bPoseChannel *pchan= tree->chain[i];
+			splineik_evaluate_bone(tree, scene, ob, pchan, i, ctime);
 		}
 		
+		/* free the tree info specific to SplineIK trees now */
+		if (tree->chain) MEM_freeN(tree->chain);
+		if (tree->free_points) MEM_freeN(tree->points);
+		
 		/* free this tree */
-		BLI_freelinkN(&pchan_root->iktree, tree);
+		BLI_freelinkN(&pchan_root->siktree, tree);
 	}
 }
 
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 9f6ce4eb79b..ba1d333f44f 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -4064,6 +4064,7 @@ static void direct_link_pose(FileData *fd, bPose *pose)
 			direct_link_motionpath(fd, pchan->mpath);
 		
 		pchan->iktree.first= pchan->iktree.last= NULL;
+		pchan->siktree.first= pchan->siktree.last= NULL;
 		
 		/* incase this value changes in future, clamp else we get undefined behavior */
 		CLAMP(pchan->rotmode, ROT_MODE_MIN, ROT_MODE_MAX);
diff --git a/source/blender/ikplugin/intern/iksolver_plugin.c b/source/blender/ikplugin/intern/iksolver_plugin.c
index 787766f0fa6..2a83052c827 100644
--- a/source/blender/ikplugin/intern/iksolver_plugin.c
+++ b/source/blender/ikplugin/intern/iksolver_plugin.c
@@ -526,12 +526,14 @@ void iksolver_execute_tree(struct Scene *scene, struct Object *ob,  struct bPose
 		
 		/* 6. apply the differences to the channels, 
 			  we need to calculate the original differences first */
-		for(a=0; a<tree->totchannel; a++)
+		for(a=0; a<tree->totchannel; a++) {
 			make_dmats(tree->pchan[a]);
+		}
 		
-		for(a=0; a<tree->totchannel; a++)
+		for(a=0; a<tree->totchannel; a++) {
 			/* sets POSE_DONE */
 			where_is_ik_bone(tree->pchan[a], tree->basis_change[a]);
+		}
 		
 		/* 7. and free */
 		BLI_remlink(&pchan->iktree, tree);
diff --git a/source/blender/makesdna/DNA_action_types.h b/source/blender/makesdna/DNA_action_types.h
index db574160771..b198231df3a 100644
--- a/source/blender/makesdna/DNA_action_types.h
+++ b/source/blender/makesdna/DNA_action_types.h
@@ -198,7 +198,9 @@ typedef struct bPoseChannel {
 	struct Bone			*bone;		/* set on read file or rebuild pose */
 	struct bPoseChannel *parent;	/* set on read file or rebuild pose */
 	struct bPoseChannel *child;		/* set on read file or rebuild pose, the 'ik' child, for b-bones */
-	struct ListBase		 iktree;		/* only while evaluating pose */
+	
+	struct ListBase		 iktree;		/* "IK trees" - only while evaluating pose */
+	struct ListBase 	siktree;		/* Spline-IK "trees" - only while evaluating pose */
 	
 	bMotionPath *mpath;				/* motion path cache for this bone */
 	struct Object *custom;			/* draws custom object instead of default bone shape */